Lansoprazole: Uses, Dosage, Side Effects & How It Compares to Omeprazole
15mg vs 30mg doses, the orodispersible Zoton FasTab, timing rules that make or break it, and how it stacks up against omeprazole.
Part of the Complete Acid Reflux Guide.
Key fact: Lansoprazole matches omeprazole for effectiveness at standard doses — but it is fussier about timing. Taken 30 minutes before food it works reliably; taken with a meal, much of the dose is wasted.
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Order Lansoprazole →What lansoprazole is and what it treats
Lansoprazole is a proton pump inhibitor (PPI) that reduces the amount of acid your stomach produces. Alongside omeprazole it is one of the two most prescribed PPIs in the UK. Unlike omeprazole and esomeprazole, it is prescription-only — there is no over-the-counter version. It is used for:
- Heartburn and acid reflux — including reflux that has inflamed the oesophagus
- GORD (gastro-oesophageal reflux disease) — both healing and long-term maintenance
- Stomach and duodenal ulcers — healing and prevention
- NSAID protection — preventing ulcers in people taking anti-inflammatory painkillers
- H. pylori eradication — as part of triple therapy with antibiotics
- Zollinger–Ellison syndrome and other acid-overproduction conditions
How lansoprazole works
Stomach acid is produced by microscopic proton pumps in the stomach lining. Lansoprazole permanently disables the pumps that are active when the drug is in your bloodstream; acid production only recovers as new pumps are built over several days. That is why one dose suppresses acid for around 24 hours, and why the full effect builds over the first few days of treatment. The mechanism is explained step by step in What is a proton pump inhibitor?
Lansoprazole dosage: 15mg and 30mg
| Dose | Typical use | Availability |
|---|---|---|
| 15mg once daily | Long-term maintenance once symptoms are controlled; NSAID protection | Prescription only |
| 30mg once daily | Standard treatment dose for GORD, oesophagitis and ulcer healing (usually 4–8 weeks) | Prescription only |
| 30mg twice daily | H. pylori eradication (with two antibiotics, for 7 days) | Prescription only |
Both strengths come as capsules or as the orodispersible FasTab. As with any PPI, the aim for long-term use is the lowest dose that controls symptoms, reviewed at least annually.
How long does lansoprazole take to work?
Most people notice clear improvement within 2–3 days, with the full effect by day 4–5. Acid reduction begins within an hour or two of the first dose, but complete relief needs several consecutive daily doses — each day’s dose knocks out more pumps. If you feel no meaningful benefit after 14 days of correct use, see a clinician rather than continuing indefinitely.
2–3
days until most people feel clear improvement
4–5
days to reach the full acid-suppressing effect
30min
before food — the timing rule that matters most
How to take lansoprazole correctly
1
Take it at least 30 minutes before food
This matters more for lansoprazole than for other PPIs: food substantially reduces its absorption. Before breakfast is ideal — set it next to the kettle as a reminder.
2
Swallow capsules whole
Do not chew or crush them — the coating protects the medicine from stomach acid. If swallowing is difficult, ask for the orodispersible FasTab instead.
3
Take it every day during your course
Lansoprazole prevents acid production; it is not an on-the-spot reliever. Keep an antacid or alginate handy for breakthrough symptoms in the first days.
4
If you miss a dose
Take it when you remember unless your next dose is nearly due — then skip it. Never double up.
Zoton FasTab: the melt-in-the-mouth option
Lansoprazole is the only major PPI available as an orodispersible tablet — Zoton FasTab — which dissolves on the tongue in seconds without water. The strawberry-flavoured tablet contains the same medicine at the same 15mg and 30mg doses. It is a practical solution for people with swallowing difficulties, those who take medicines on the go, and anyone who gags on capsules. If that is you, ask for it by name in your consultation.
Lansoprazole side effects
Common (up to 1 in 10 people)
- Headache
- Diarrhoea or constipation
- Nausea, stomach pain or wind
- Dry or sore mouth
Uncommon and rare
- Dizziness, fatigue, itching or rash
- Low magnesium with long-term use (fatigue, muscle twitches or cramps)
- Very rarely: severe skin reactions, liver problems or kidney inflammation — seek help for unexplained rash with fever, yellowing skin or a marked drop in urine
Long-term considerations
The long-term evidence for lansoprazole mirrors the PPI class as a whole: modest associations with bone fracture, vitamin B12 deficiency, low magnesium and certain gut infections after years of use. Appropriate long-term use — lowest effective dose, annual review — keeps the balance firmly in favour of treatment where it is needed. Full details in the complete PPI guide.
Lansoprazole vs omeprazole
The short answer: they are equally effective for most people. Head-to-head trials at standard doses show comparable symptom relief and healing rates. The differences that actually influence the choice are practical:
| Lansoprazole | Omeprazole | |
|---|---|---|
| Standard dose | 30mg once daily | 20mg once daily |
| Availability | Prescription only | OTC (20mg, max 14 days) or prescription |
| With clopidogrel | Usually preferred | Avoided — reduces clopidogrel’s effect |
| Swallowing difficulties | Orodispersible FasTab available | Capsules/tablets only |
| Food timing | Strict: 30+ minutes before food | Before food preferred, less critical |
For the full three-way comparison including esomeprazole, see Omeprazole vs Lansoprazole vs Esomeprazole.
Interactions to know about
Lansoprazole has fewer clinically important interactions than omeprazole, which is one reason prescribers choose it — notably it is the usual PPI choice for people taking clopidogrel. Still, tell your prescriber if you take: methotrexate (levels can rise), digoxin, theophylline (lansoprazole can lower its levels), or medicines that need stomach acid to absorb, such as itraconazole and some HIV medicines. St John’s Wort can make lansoprazole less effective.
Seek urgent help if you have difficulty swallowing, vomit blood or dark material like coffee grounds, pass black tarry stools, or are losing weight without trying — these need investigation first. Chest pain with breathlessness or pain spreading to arm or jaw: call 999.
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Complete a short online consultation and our pharmacist independent prescribers will confirm whether lansoprazole — capsules or FasTab — is right for you.
Start Your Consultation →Frequently Asked Questions
Is lansoprazole stronger than omeprazole?
No — at standard doses (lansoprazole 30mg, omeprazole 20mg) the two provide comparable acid suppression and symptom relief for most people, and head-to-head trials show no consistent winner. What differs is formulation (lansoprazole has an orodispersible tablet), interactions (lansoprazole is usually preferred with clopidogrel) and individual response.
Why must lansoprazole be taken 30 minutes before food?
Food significantly reduces the absorption of lansoprazole, so taking it at least 30 minutes before eating — usually before breakfast — can make the difference between a medicine that works and one that seems not to. It also times peak drug levels with the meal-triggered activation of acid pumps, which is when a PPI works best.
How long does lansoprazole take to work?
Some acid reduction begins within an hour or two of the first dose, but most people notice clear improvement in 2 to 3 days, with the full effect by day 4 or 5. Give it a fair trial of at least a week before judging it, and seek a review if there is no meaningful improvement after 14 days.
Can I take lansoprazole every day?
Yes — lansoprazole is prescription-only in the UK, and many people take it daily for months or years under medical supervision, particularly for GORD. The principle for any long-term PPI is the lowest dose that controls symptoms, reviewed at least once a year.
What is Zoton FasTab?
Zoton FasTab is a branded orodispersible form of lansoprazole that melts on the tongue without water. It contains the same medicine at the same doses (15mg and 30mg) and is particularly useful for people who struggle to swallow capsules — a common problem in the very group who need reflux treatment.
Can I switch between lansoprazole and omeprazole?
Yes, switching is straightforward and often done when one PPI causes side effects or does not suit you. Standard doses are broadly equivalent (lansoprazole 30mg roughly matches omeprazole 20mg), and no washout period is needed — you simply take the new medicine from the next day. Make the switch through a prescriber rather than on your own.
Getting lansoprazole from Access Doctor
Access Doctor’s pharmacist independent prescribers can prescribe lansoprazole — capsules or orodispersible — following a short online consultation, with discreet delivery across the UK.
Acid Reflux · Rx
Lansoprazole
Once-daily acid suppression — the usual choice alongside clopidogrel.
View product →Acid Reflux · Rx
Omeprazole
The UK’s most prescribed PPI — comparable relief, different timing rules.
View product →Acid Reflux · Rx
Esomeprazole
A stronger option for severe or persistent reflux symptoms.
View product →Consultation
Acid Reflux Treatment
Not sure which is right? Start a consultation and we’ll advise.
Start consultation →References
- National Institute for Health and Care Excellence. Gastro-oesophageal reflux disease and dyspepsia in adults: investigation and management (CG184). 2019. nice.org.uk
- NHS. Lansoprazole. 2023. nhs.uk
- Joint Formulary Committee. British National Formulary: Lansoprazole. 2026. bnf.nice.org.uk
- Electronic Medicines Compendium. Lansoprazole 30mg gastro-resistant capsules: Summary of Product Characteristics. 2025. medicines.org.uk
- Graham DY, Tansel A. Interchangeable use of proton pump inhibitors based on relative potency. Clinical Gastroenterology and Hepatology. 2018. pubmed.ncbi.nlm.nih.gov
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.